Shape memory material seals

ABSTRACT

The invention relates to a shape memory sleeve to create an annular tightness. More precisely, the invention relates to a ring to provide tightness, made from shape memory alloy material and including an interior annular portion and an exterior annular portion, comprising at least one annular groove or one annular rib on its interior annular portion.

FIELD OF THE INVENTION

This invention relates to tubings and seals for application in thepetroleum sector and more particularly the invention comprises formingan annular tightness via a shape memory sleeve.

PRIOR ART

In the petroleum sector, each tool, whether for permanent use(installation at the bottom of a well for permanent use) or for use whenit is taken down to the bottom of the well, must withstand ratherdrastic temperature and pressure constraints, which implies that thetightness for these tools is today formed substantially via welding. Thetightness protects the electronics or the cabling against wellenvironment. In case of a failure of the electronics, disassemblybecomes complicated and risky since the welds must be ground, runningthe risk of destroying the entire tool, and the involved parts must bemachined and the welding procedure must be started again on site,calling on an outsider welder.

The purpose of the invention is to replace certain annular tight weldsof subsets that are complex and difficult to move and which can only beperformed on site, with a tight obtained via press fit of a shape memorysleeve. The assembly of the subset can be carried out in a workshop andthe press fit using a hot air gun on site or in the workshop, as isconvenient. As such, the major advantages are to simplify assembly inthe field, reduce the overall cost and assembly time.

SUMMARY OF THE INVENTION

The invention puts forth a ring for providing tightness, made of a shapememory alloy material and including an interior annular portion and anexterior annular portion, and comprising at least one annular groove orone annular rib on its interior annular portion. This ring can morepreferably include several annular grooves or annular ribs on itsinterior annular portion.

In another embodiment, the invention discloses a plug for providingtightness, made of a shape memory alloy material and comprising anexterior annular portion, and comprising at least one annular groove orone annular rib on its exterior annular portion. This plug can morepreferably comprise several annular grooves or annular ribs on itsinterior annular portion.

Another aspect of the invention proposes a method for realizing thetightness of a well-bottom tool, comprising the step of using an elementsuch as described previously.

A method for realizing the tightness of a well-bottom tool is alsodisclosed, comprising the selection of two elements to be assembled in atight manner, the selection of a ring made of a shape memory alloymaterial in its non permanent mode to assemble said elements in a tightmanner, the realization of at least one annular rib on the interiorportion of said ring and the positioning of said ring in permanent modeby heating to a given temperature such that said ring provides thetightness of said two elements. Incidentally, an annular groove can alsobe used; a combination of the two groove/rib on the two elements is alsopossible.

Then, a method for realizing the tightness of a well-bottom tool is alsodisclosed, comprising the selection of two elements to assemble in atight manner, the selection of a ring made of a shape memory alloymaterial in its non permanent mode in order to assemble said elements ina tight manner, the realization of at least one annular rib on one ofthe two elements and the positioning of said ring in permanent mode byheating to a given temperature such that said ring provides thetightness of said two elements. Incidentally, an annular groove can alsobe used; a combination of the two groove/rib on the two elements is alsopossible.

Finally, a method for realizing the tightness of a well-bottom tool isalso disclosed, comprising the selection of an element with holes toplug in a tight manner, the selection of a plug made of a shape memoryalloy material in its non permanent mode to fill and seal said hole ofthe element, the realization of at least one annular rib on said plugand the positioning of said plug in said hole in permanent mode byheating to a given temperature such that said plug provides thetightness of the element with holes. Incidentally, an annular groove canalso be used; a combination of the two groove/rib on the two elements isalso possible.

The preceding methods more preferably include a shape memory alloymaterial which is Nickel Titane Niobium with 14% niobium and the giventemperature is approximately 165° C.

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments of the invention can be understood with more detail inthe attached drawings:

FIG. 1 shows machine-tooled ribs inside the ring.

FIG. 2 shows machine-tooled ribs inside a support.

FIG. 3 shows machine-tooled ribs on any metallic support.

FIG. 4 shows an example of a plug relating to the invention.

FIG. 5 shows an electrical connection relating to the invention.

DETAILED DESCRIPTION

The material used as a shape memory alloy is Nickel Titanium Niobiumwith 14% niobium NiTiNb. This material has the particularity of startingfrom a dimensional state A, via low-temperature deformation, it is thenchanged to a dimensional state B (B being higher than A). It remains instate B at room temperature and this, up to 50° C. In this state B, itcan therefore be used and assembled on the well tools. Then, by heatingit to 165° C. it will return to its dimensional state A, that it willmaintain within a temperature range of −60° C. to +300° C.

The tightness is formed by a metal-on-metal tightness realized byannular grooves or ribs. This tightness is maintained by a press fittedring. The ribs are machine tooled on the ring. Realization of thetightness is provided by ribs and the maintaining of this tightness isprovided by a press fitted ring made from shape memory alloy (SMA).Effectively, the tightness is realized by crushing the annular rib onthe tubular support. FIG. 1 shows annular ribs 3 machine tooled insideSMA ring 1. By heating the ring, the latter decreases in diameter andsqueezes the ribs on tube 2 in order to form the tightness.

In a second embodiment, the same tightness can be realized by machiningthe ribs on the support rather than on the ring. FIG. 2 shows ribs 3machine tooled inside a support 4. By heating ring 1, the latterdecreases in diameter and squeezes the ribs on a ‘¼ liner’ 5 and formsthe tightness.

In a third embodiment, a tightness can also be realized on composite orplastic materials such as PEEK (registered trademark), by machining theribs on the metallic support then by covering the whole with a plastictube and by maintaining the tightness via the press fit of the SMA ring.FIG. 3 shows the machine-tooled ribs 3 on a metallic tube 2, a plastictube 6 covers the ribs. By heating ring 1, the diameter of the latterdecreases and squeezes the tube on the ribs and forms the tightness.

In a fourth embodiment, a tightness can also be realized with a plug, bymachine tooling ribs on the plug. The plug is made from SMA. Thediameter of the plug increases after heating and forms thanks to theribs, the tightness in its housing. FIG. 4 shows an example of an SMAplug 10, by heating the plug its length decreases and its diameterincreases and forms the tightness of a support 12.

In a fifth embodiment, the squeezing of the ring can be used to realizean electrical continuity of a contact on another contact. This avoidsbrazing them together. FIG. 5 shows an electrical connection 7, insteadof forming the electrical continuity by a braze (which is done forpermanent tools). An SMA ring 1 is used to squeeze the split electricalcontact 21 on the second electrical contact 20 in such a way as torealize the electrical continuity as well as its mechanical maintaining.The advantage is to simplify the procedure and avoid recourse to manualknow-how for the braze.

1. Ring for providing tightness, made of a shape memory alloy materialand including an interior annular portion and an exterior annularportion, and comprising at least one annular groove or one annular ribon its interior annular portion.
 2. Ring according to claim 1,comprising several annular grooves or annular ribs on its interiorannular portion.
 3. Plug for providing tightness, made of a shape memoryalloy material and comprising an exterior annular portion, andcomprising at least one annular groove or one annular rib on itsexterior annular portion.
 4. Plug according to claim 3, comprisingseveral annular grooves or annular ribs on its exterior annular portion.5. Method for realizing the tightness of a well-bottom tool, comprisingthe step of using an element such as described in claim
 1. 6. Method forrealizing the tightness of a well-bottom tool, comprising the selectionof two elements to assemble in a tight manner, the selection of a ringmade of shape memory alloy material in its non permanent mode in orderto assemble said elements in a tight manner, the realization of at leastone annular rib on the interior portion of said ring and the positioningof said ring in permanent mode by heating to a given temperature suchthat said ring provides the tightness of said two elements.
 7. Methodfor realizing the tightness of a well-bottom tool, including theselection of two elements to be assembled in a tight manner, theselection of a ring made from shape memory alloy material in its nonpermanent mode in order to assemble said elements in a tight manner, therealization of at least one annular rib on one of the two elements andthe positioning of said ring in permanent mode by heating to a giventemperature such that said ring provides the tightness of said twoelements.
 8. Method for realizing the tightness of a well-bottom tool,including the selection of an element with holes to plug in a tightmanner, the selection of a plug made from shape memory alloy material inits non permanent mode to fill said hole of the element in a tightmanner, the realization of at least one annular rib on said plug and thepositioning of said plug in said hole in permanent mode by heating to agiven temperature such that said plug provides the tightness of theelement with holes.
 9. Method according to claim 6, wherein the shapememory alloy material is Nickel Titanium Niobium with 14% niobium andthe given temperature is approximately 165° C.